An example of conventionally known liquid crystal display (LCD) device includes an optical stack including, in sequence, a transparent front plate, an ultraviolet (UV)-curable adhesive layer, a polarizing plate, a pressure-sensitive adhesive layer, and a transparent substrate. The UV-curable adhesive layer is formed of a UV-curable adhesive composition containing an acrylic ester monomer having an ester moiety having 6 to 11 carbon atoms. Exerting 3 kg load on the pressure-sensitive adhesive layer that has been attached on an alkali-free glass substrate over an area of 25 mm×25 mm will results in creep in a range from 90 to 1,000 μm after 3,000 seconds under conditions of a temperature of 23° C. and a relative humidity of 55%. An example of such a liquid crystal display (LCD) device is disclosed in Japanese Unexamined Patent Application Publication No. 2014-213488.
The technology described in Japanese Unexamined Patent Application Publication No. 2014-213488 has a configuration in which the transparent front plate is stacked on the liquid crystal display device using the UV-curable adhesive layer disposed therebetween. This configuration prevents deformation, by the UV-curable adhesive layer, of the pressure-sensitive adhesive layer that bonds the polarizing plate to the transparent substrate, thereby preventing uneven reflection. In the liquid crystal display device, turn-on of a power supply causes a heat-generating component such as a light source to generate heat, thereby causing thermal expansion of a component, while turn-off of the power supply causes thermal shrinkage of a component. A transparent substrate and a transparent front plate of a liquid crystal panel, each being a large-sized component in a liquid crystal display device, significantly expand or shrink in thermal expansion or in thermal shrinkage. Therefore, a difference in the linear expansion coefficient among the transparent substrate, the transparent front plate, and the UV-curable adhesive layer stacked one on top of another may cause stress to act on these components. In recent years, the polarizing plate may also have a phase difference function for purposes such as viewing angle compensation. During use of such a polarizing plate, action of the stress mentioned above on the liquid crystal panel may cause an uneven color region, where a displayed color differs from the intended color, to occur locally in and near a region where the stress acts.